اذا لم تجد ما تبحث عنه يمكنك استخدام كلمات أكثر دقة.
العُنْصُر الخَامِس عَشَر:- a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms (Arabic WordNet)